EFFECT OF FISH OIL
General information about fish oil
Fish oil can be found in fish or supplements. Fish is particularly rich in omega-3 fatty acids, including mackerel, tuna, salmon, sturgeon, bluefin, anchovies, sardines, herring, cod liver, and halibut. Two of the most important omega-3 fatty acids found in fish oil are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Fish oil supplements are usually made from mackerel, herring, tuna, halibut, salmon, cod liver, whale. Fish oil supplements often contain little vitamin E to avoid rapid spoilage. They can also combine with calcium, iron or vitamins A, B1, B2, B3, C or D.
Some fish oil is used as a prescription drug, to lower triglyceride levels. However, for the most part, fish oil is used as a dietary supplement in many health conditions, often related to the cardiovascular system and blood. Some people use fish oil to lower blood pressure or triglyceride levels (fats related to cholesterol). Fish oil is effective in preventing heart disease or stroke. Scientific evidence shows that fish oil actually lowers high triglyceride levels and may also help prevent heart disease and stroke when taken in recommended doses, as if overdosed, can increase the risk of stroke.
Fish oil is also used for many kidney problems.
However, the well-known effect of fish oil is “brain food”. Since some people eat fish to improve various conditions related to neurological and brain functions such as depression, mental illness, attention deficit hyperactivity disorder (ADHD), Alzheimer’s disease and other thinking disorders.
Some people use fish oil to reduce age-related dry eye, glaucoma and age-related eye degeneration (AMD) – a very common condition in older adults that can lead to serious problems about the eye.
Women sometimes use fish oil to prevent painful periods; breast pain and pregnancy-related complications such as miscarriage, late high blood pressure, premature delivery.
Fish oil is also used to treat diabetes, asthma, developmental coordination disorders, movement disorders, dyslexia, obesity, kidney disease, weak bones (osteoporosis), certain related diseases to pain and swelling like psoriasis, and prevent weight loss due to some cancer drugs.
Fish oil is occasionally used after heart transplant surgery to prevent high blood pressure and kidney damage from surgery or medications used to reduce the risk of a new heart reaction. Fish oil is sometimes used after coronary artery bypass surgery.
What is the mechanism of action of fish oil?
Many of the benefits of fish oil come from the omega-3 fatty acids contained in it. An unexpected fact is that the body does not produce omega-3 fatty acids on its own. Nor does the body make omega-3 fatty acids from omega-6 fatty acids.
Omega-3 fatty acids reduce pain and swelling. Therefore it is effective for psoriasis and dry eyes. These fatty acids also help prevent blood clots, which are helpful for some heart conditions.
Effect of fish oil
Cases that fish oil are effective
People with high fat content (hypertriglyceridemia). Most studies show that fish oil can reduce triglyceride levels by 20% to 50%. More effective in people with higher triglyceride levels. In addition, taking a larger amount of fish oil will reduce triglyceride levels. But fish oil seems to have a smaller effect than a drug called fibrate. Some fish oil preparations, including Lovaza, Omtryg and Epanova, are approved as prescription medications to treat very high levels of triglycerides. These products are usually taken in doses of 4 grams per day, including 3.5 grams of omega-3 fatty acids. Some over-the-counter fish oil supplements often contain less omega-3 fatty acids than prescription fish oil products. So the dose can be up to 12 capsules daily, to get the same effect as prescription fish oil.
Cases that fish oil may be effective
Blood vessels are blocked or narrowed (angioplasty). Research shows that fish oil reduces the incidence of embolism by up to 45% when administered at least 3 weeks before angioplasty, and continues to work for a month afterwards. However, when it was injected for 2 weeks before angioplasty, it did not seem to work.
Miscarriage in pregnant women with an autoimmune disorder called antiphospholipid syndrome. Taking fish oil by mouth to avoid miscarriage and increase survival in pregnant women with antiphospholipid syndrome.
Attention deficit hyperactivity disorder (ADHD) in children. Early research suggests that taking fish oil improves attention, mental function and behavior in children aged 8-13 with ADHD.
Bipolar disorder. Taking fish oil along with conventional treatments helps improve bipolar disorder, but depressive symptoms. But it is not effective for mania in people with bipolar disorder.
Voluntary weight loss in people who are seriously ill (asthenic syndrome). Taking high-dose fish oil slows down weight loss in some cancer patients. Low dose fish oil does not seem to have this effect. Some researchers believe that fish oil slows cancer-related weight loss by fighting depression and improving the mood of people with cancer.
Surgery to improve blood flow to the heart (CABG surgery). Taking fish oil helps prevent coronary arteries from sticking after CABG surgery.
High blood pressure, kidney damage caused by cyclosporine. Cyclosporine is a drug that reduces organ rejection after transplantation. Taking fish oil helps prevent high blood pressure, kidney damage caused by taking this drug. Fish oil also improved kidney function during the recovery period, after the body rejected a transplant organ in cyclosporine users.
Developmental coordination disorder or DCD. The combination of fish oil (80%) and evening primrose oil (20%) appears to improve reading, spelling and behavior when children aged 5-12 years have DCD.
Dysmenorrhea. Research shows that taking fish oil alone or with vitamin B12 or vitamin E may reduce pain duration and reduce the need for pain medication in women with dysmenorrhea.
Endometrial cancer (endometrial cancer) There is some evidence that women who regularly eat about two servings of fatty fish weekly will reduce the risk of developing endometrial cancer.
Heart failure. Higher intake of fish oil from foods helps reduce the risk of heart failure. Eat 1-2 portions of non-fried fish each week.
Complications after heart transplant. Taking fish oil helps preserve kidney function and reduce long-term hypertension after a heart transplant.
Abnormal blood fat levels in people with HIV / AIDS. Some studies show that taking fish oil reduces triglyceride levels in people with abnormal cholesterol levels due to HIV / AIDS treatment. Taking fish oil may also lower total cholesterol levels in these people.
High Blood Pressure. Fish oil seems to reduce blood pressure slightly in people with moderate to very high blood pressure. Some fish oils may also lower blood pressure in people with high blood pressure, but the results are inconsistent.
IgA kidney disease. Some studies suggest that long-term use of fish oil may slow kidney function loss in patients at high risk of IgA kidney disease. Fish oil may have a greater effect when taken in higher doses. In addition, it may be most effective in people with IgA kidney disease who have a higher amount of protein in the urine.
Weak and brittle bones (osteoporosis). Research shows that taking fish oil individually or together with calcium and evening primrose oil slows down the rate of bone loss and increases bone density in the femur (femur) and spine in elderly people with osteoporosis. But taking fish oil does not slow down the process of bone loss in the elderly with knee osteoarthritis but no weak bones.
Psoriasis. There is some evidence that injecting fish oil into a vein (by IV) may reduce the severity of psoriasis symptoms. In addition, applying fish oil to the skin seems to improve some symptoms of psoriasis. But taking fish oil seems to have no effect on psoriasis.
Mental disorders have hallucinations and delusions (psychosis). Some studies suggest that taking fish oil supplements may help prevent mental illness from fully developing in mildly ill teens and young adults. The effects of fish oil have not been tested in older adults.
Raynaud’s syndrome. There is some evidence that taking fish oil can improve cold tolerance in some people with the common form of Raynaud’s syndrome. However, people with Raynaud’s syndrome caused by a condition called progressive systemic sclerosis do not seem to benefit from taking fish oil supplements.
Rheumatoid arthritis (RA). Taking fish oil alone or together with naproxen (Naprosyn), seems to help improve symptoms of RA. In addition, intravenous fish oil (by IV) reduces swelling and joint pain in people with RA.
Cases that fish oil may not be effective
Chest pain (angina). Research shows that fish oil supplements do not reduce the risk of death or improve heart health in people with chest pain. Some evidence even suggests that fish oil supplements may actually increase the risk of heart-related death in people with chest pain.
Arteriosclerosis (atherosclerosis). Some studies suggest that taking fish oil supplements may alleviate the process of atherosclerosis. But most studies show that fish oil does not slow progression or improve atherosclerotic symptoms.
Eczema (atopic dermatitis). Research shows that fish oil does not improve eczema. Most studies also show that taking fish oil during pregnancy does not cause eczema in children. Providing fish oil to infants also does not seem to prevent eczema in children. But children who eat fish at least once a week between 1-2 years old seem to be at a lower risk of eczema.
Irregular heartbeat (atrial fibrillation). Some studies show that people who eat fish five or more times a week reduce the risk of an irregular heartbeat. But most studies show that eating fatty fish or taking fish oil supplements does not reduce the risk of an irregular heartbeat.
Problems with long-term blood flow in the brain (cerebrovascular disease). Some early studies suggest that eating fish reduces the risk of cerebrovascular disease. But higher quality research shows that taking fish oil does not have this effect.
Scarring of the liver (cirrhosis). Taking fish oil does not seem to improve kidney problems associated with liver scarring due to progressive liver disease.
Memory and thinking skills (cognitive functions). Most studies show that fish oil supplements do not improve mental function in the elderly, young people or children.
A mild form of gum disease (gingivitis). Taking fish oil does not seem to improve gingivitis.
Infections of the digestive tract can lead to ulcers (Helicobacter pylori or H. pylori). Taking fish oil does not seem to improve H. pylori infection when compared to standard drugs.
HIV AIDS. There is some evidence that supplementing with fish oil supplements does not increase CD4 cell counts in people with human immunodeficiency virus (HIV). In addition, drinking formula containing fish oil does not seem to reduce the amount of HIV in the blood.
Kidney transplant. Research shows that taking fish oil does not help people live longer after a kidney transplant. It also does not seem to prevent the body from refusing to implant.
Breast pain (chest pain). Taking fish oil does not relieve breast pain in the long term.
Menopausal symptoms. Research shows that fish oil does not reduce symptoms of hot flashes, insomnia or increase the quality of life in women with these symptoms. However, fish oil supplements may reduce night sweats in these women.
Migraine. Taking fish oil by mouth does not seem to reduce the number or severity of migraines.
Osteoarthritis. People with osteoarthritis taking low-dose fish oil seem to be less painful and perform better than those taking high-dose fish oil. This result is somewhat unexpected and may be due to the “placebo effect”. Adding fish oil to glucosamine will not reduce pain or stiffness compared to taking glucosamine alone.
Narrowing of blood vessels causes poor blood flow to the extremities (peripheral artery disease). Taking fish oil does not seem to improve walking distance in people with leg pain due to flow problems.
Pneumonia. Population studies show no relationship between fish consumption and the risk of developing pneumonia.
High blood pressure during pregnancy. Fish oil does not seem to prevent high blood pressure during pregnancy.
Preeclampsia. Fish oil does not seem to prevent pre-eclampsia.
Abnormal tachycardia (ventricular arrhythmia). Population studies show that eating a lot of fish does not affect the risk of abnormal tachycardia. Clinical studies are not consistent. Some studies show that taking fish oil daily does not affect the risk of abnormal heart rhythms. However, other research shows that taking fish oil for 11 months will slow the development of this condition. However, in general, taking fish oil does not seem to reduce the risk of death in people with abnormal tachycardia.
Diabetes. Taking fish oil does not lower blood sugar levels in people with type 2 diabetes. However, fish oil may provide some other benefits for people with diabetes, such as reducing blood fat called triglycerides. In addition, fish oil does not reduce the risk of diabetes during pregnancy.
Cases that fish oil have insufficient evidence
Age-related macular degeneration or AMD. There is some evidence that people who eat fish more than once per week reduce their risk of developing age-related vision loss. But, clinical research shows that taking fish oil by mouth up to 5 years does not prevent vision loss.
Allergy. Early research suggests that mothers taking fish oil supplements in late pregnancy may reduce the occurrence of allergies in children. But other research shows that fish oil does not reduce the development of allergies in children when the mother takes it during pregnancy.
Alzheimer. There is some preliminary evidence that fish oil may help prevent Alzheimer’s disease. However, it does not seem to help prevent a decline in thinking skills for most people who have been diagnosed with Alzheimer’s.
Asthma. Some studies suggest that fish oil supplements may help treat some asthma symptoms. But the results did not match. Some studies show that taking fish oil improves breathing and reduces the need for medication. Another study found that fish oil did not reduce the severity of asthma in children. Fish oil can help prevent childhood asthma when a mother takes it during pregnancy. But fish oil does not seem to provide any benefit when a mother takes it while breastfeeding or a newborn. Overall, research shows that fish oil does not help treat eczema once it has developed.
Sports performance. There is some evidence that taking fish oil may improve lung function in athletes. But other evidence suggests that taking fish oil doesn’t improve stamina, recovery, heart rate or duration of exercise.
Autism. One small study found that taking fish oil may reduce hyperactivity in autistic children. But this study is flawed. Another study found that taking fish oil did not reduce hyperactivity.
Cancer. Research on the effects of fish oil in preventing cancer has produced conflicting results. Some studies involve eating fish or having higher levels of omega-3 fatty acids in the risk of various cancers. However, other research shows that eating fish doesn’t reduce the risk of cancer.
Heart disease. Most studies show that fish oil supplements do not prevent heart disease or reduce the risk of heart disease in people with heart disease. Getting fish oil from the diet may be beneficial. But the benefit is probably the most modest. People should still eat fish and other foods that provide fish oil, though. These foods are part of a healthy diet.
Cataract. There is some preliminary evidence that eating fish three times a week can slightly reduce the risk of developing cataracts.
Chronic fatigue syndrome (CFS). There is some conflicting evidence about the use of a specific product (Efamol Marine) that combines fish oil and evening primrose oil to reduce CFS symptoms.
Memory impairment and thinking skills in older adults are more common than their age. Some studies show that taking fish oil daily for 12 months can improve memory in people with impaired mental function.
Colon cancer, rectal cancer. Some early studies suggest that taking fish oil during chemotherapy may slow tumor progression in people with colorectal cancer.
A type of inflammatory bowel disease (Crohn’s disease). Research on the effects of fish oil on Crohn’s disease has produced conflicting results. Some studies suggest that taking a specific fish oil product can reduce Crohn’s disease recurrence for those who have recovered. However, other studies show that fish oil does not have this effect.
Cystic fibrosis. Early research suggests that taking fish oil by mouth may improve lung function in people with cystic fibrosis. However, administration of intravenous (IV) fish oil did not have this effect.
Depression. People who eat a lot of fish seem to have a lower risk of depression. But it is unclear if taking fish oil supplements reduces the symptoms of depression. Results from research are conflicting. Reasons for the differences may be related to fish oil dosage, omega-3 fatty acid ratio in fish oil supplementation and the level of depression before treatment.
Kidney damage in people with diabetes (diabetic kidney disease). Evidence shows that taking fish oil does not improve kidney function in people with diabetic kidney disease.
Vision problems in people with diabetes (diabetic retinopathy). Higher intake of fish oil from the diet is associated with a reduced risk of eye damage in people with diabetes.
Dry eyes. Higher intake of fish oil from the diet is associated with a lower risk of dry eye in women. But the effects of fish oil in people with dry eyes are inconsistent. Some studies show that fish oil reduces the symptoms of dry eyes such as pain, blurred vision and sensitivity. But fish oil does not seem to improve other signs and symptoms of dry eyes such as tear production and damage to the surface of the eye. Taking fish oil also did not improve the signs and symptoms of dry eyes when used with other dry eye treatments.
Dyslexia. Taking fish oil by mouth seems to improve night vision in children with dyslexia.
Abnormal cholesterol or blood cholesterol levels (dyslipidemia). There is conflicting data on the effects of fish oil on blood fats in people with abnormal blood fats. Research shows that eating two servings of fish per week can lower cholesterol and cholesterol in people with high cholesterol. Taking fish oil supplements also seems to improve triglyceride levels and some other blood fats in people with diabetes and in kidney transplant recipients. But most studies show that fish oil supplements do not improve cholesterol levels in people with abnormal or high cholesterol levels. In fact, taking fish oil supplements may actually increase low-density lipoprotein (LDL or “bad”) cholesterol levels in these people.
Severe kidney disease (end-stage renal disease or ESRD). Some evidence suggests that taking fish oil reduces the signs of swelling (inflammation) in people with severe kidney disease.
Seizures (epilepsy). Research shows that taking omega-3 fatty acids from fish oil daily for 10 weeks reduces seizures in people with drug-resistant epilepsy.
Muscular aches due to exercise. Taking fish oil can reduce exercise-induced muscle soreness in professional athletes. But these preliminary results need to be confirmed in larger, high quality studies. It is not known whether fish oil reduces exercise-induced muscle soreness in an untrained adult. The results from the original study were conflicting.
Food allergy. Taking fish oil during pregnancy appears to reduce the risk of an egg allergy in a newborn. But it does not reduce the risk of other food allergies like milk or peanut allergy in infants.
Prevent obstruction used in dialysis. Taking fish oil seems to help prevent blood clot formation during hemodialysis. It can also help puzzle pieces work longer. But more research is needed to find out which dose of fish oil is best.
Prediabetes. Taking fish oil does not seem to improve blood sugar levels in people with prediabetes. But it can help prevent prediabetes from progressing to type 2 diabetes.
Multiple sclerosis (MS). Taking a specific fish oil product does not seem to improve the time, frequency or severity of relapses in patients with multiple sclerosis.
Fatty accumulation in the liver in people who drink little or no alcohol (non-alcoholic fatty liver disease or NAFLD). Limited research suggests fish oil may benefit NAFLD in adults and children.
Fat. Most studies show that taking fish oil does not improve weight loss in obese adults or children. But eating fish as part of a reduced-calorie diet seems to be helpful.
Swelling (inflammation) and sores inside the mouth (inflammation of the oral mucosa). Taking fish oil seems to reduce the severity and pain of mouth ulcers from cancer drugs.
Swelling (inflammation) of the pancreas (pancreatitis). Evidence shows that intravenous (IV) feeding with fish oil-fortified nutrition reduces the number of days of renal replacement therapy needed for people with severe pancreatitis.
An inherited disorder that raises the concentration of phenylalanine in the blood (urinary phenylketon or PKU). There is some evidence that supplementing with fish oil improves motor skills, coordination, and vision in children with a rare genetic disorder called phenylketonuria.
A type of anxiety often develops after a horrific event (post-traumatic stress disorder or PTSD). Some early studies suggest that supplementing with fish oil omega-3 fatty acids in psychotherapy does not bring any additional benefits for people with PTSD.
Premature birth. Taking fish oil or eating seafood during pregnancy can help prevent preterm birth. But conflicting results exist.
Growth and development in premature babies. Baby formula fortified with fatty acids from fish oil and borage oil appears to improve nervous system growth and development in preterm infants, especially boys.
Airway infection. Drinking beverages containing fish oil, vitamin D and protein does not seem to reduce upper respiratory infections in athletes.
Schizophrenia. Fish oil may improve symptoms such as aggression in people with schizophrenia. But not all studies agree.
Septicemia (sepsis). Providing fish oil as part of a nutrition plan for sepsis patients can reduce the need for mechanical breathing and shorten the time spent in a hospital intensive care unit. But giving fish oil does not improve survival or reduce the risk of brain injury or delirium in people with sepsis.
Sickle cell disease. Early research suggests that taking fish oil may reduce severe pain in people with sickle cell disease.
Stroke. Taking fish oil as a supplement does not seem to prevent stroke. The effectiveness of eating fish oil in the diet at risk of stroke is controversial. Eating fish once or twice a week seems to reduce the risk of stroke by 27%. But eating very high amounts of fish (more than 46 grams of fish per day) seems to increase the risk of stroke. And eating fish does not reduce the risk of stroke in people who have taken aspirin for prevention.
More evidence is needed to evaluate fish oil for these uses.
Safety and side effects
Fish oil can be safe for most people when taken in low doses (3 grams or less per day). There are some safety concerns when fish oil is used in high doses. Taking more than 3 grams per day can keep blood from clotting and may increase the likelihood of bleeding.
High doses of fish oil may also reduce the activity of the immune system, reducing the body’s ability to fight infections. This is a particular concern for people taking drugs to reduce the activity of the immune system (such as organ transplant patients) and the elderly.
Only use high doses of fish oil under the supervision of a doctor.
Fish oils can cause side effects including belching, bad breath, heartburn, nausea, loose stools, rashes and nosebleeds. Taking fish oil supplements with meals can often reduce these side effects. Certain types of fish (especially sharks, king mackerel and farmed salmon) can be contaminated with mercury and industrial chemicals from the environment.
Fish oil may be safe when given intravenously (by IV) for a short time. A solution of fish oil or omega-3 fatty acids is safely used for 1 to 4 weeks.
Special precautions & warnings
Children. Fish oil can be safe when taken appropriately. Fish oil has been used safely through feeding tubes for infants up to 9 months. But young children should not eat more than two ounces of fish per week. Fish oil is not safe when derived from foods such as mercury toxins. Eating contaminated fish regularly can cause brain damage, mental retardation, blindness and seizures in children.
Pregnant and lactating women. Fish oil may be safe to take by mouth appropriately. Taking fish oil during pregnancy does not seem to affect the fetus or baby during breastfeeding. Women who are pregnant or may become pregnant, and nursing mothers should avoid sharks, swordfish, king mackerel and tilefish (also called yellow sea bass or yellow snapper), as these can contain high levels of mercury.
Bipolar disorder. Taking fish oil may increase some of the symptoms of this condition.
Liver disease. Fish oil may increase the risk of bleeding in people with liver scars caused by liver disease.
Diabetes. There is some concern that taking fish oil in high doses may make blood sugar control more difficult.
Family adenomatous polycystic acid. There is some concern that fish oil may increase the risk of cancer in people with this disease.
High blood pressure. Fish oil can lower blood pressure and can cause blood pressure to drop too low in people being treated with antihypertensive drugs.
HIV/AIDS and other conditions reduce the immune system’s response. Higher doses of fish oil may reduce the response of the body’s immune system. This can be a problem for people with weakened immune systems.
Implantable defibrillators (a device operated to prevent irregular heartbeats). Some, but not all, studies show that fish oil may increase the risk of irregular heart rhythms in patients using implantable defibrillator. Stay safe by avoiding fish oil supplements.
Fish or seafood allergy. Some people with seafood allergies like fish may also be allergic to fish oil supplements. There is no reliable information that indicates the possibility that people with seafood allergies are likely to be allergic to fish oil. Until more is known, recommend that patients allergic to seafood should avoid or use fish oil supplements with caution.
Drug interactions
Be careful when using fish oil in combination
Birth control pills (birth control pills) interact with fish oil
Fish oil seems to help reduce the amount of fat in the blood. These fats are called triglycerides. Birth control pills can reduce the effectiveness of fish oil by reducing the amount of fat in the blood. Some types of birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
High blood pressure medications (antihypertensive drugs) interact with fish oil
Fish oil seems to reduce blood pressure. Taking fish oil along with medications to treat high blood pressure can cause the blood pressure to drop too low. Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.
Orlistat (Xenical, Alli) interacts with fish oil
Orlistat (Xenical, Alli) is used for weight loss. It prevents fat from the diet from being absorbed into the intestine. There is some concern that orlistat (Xenical, Alli) may also reduce fish oil absorption when they are taken together. To avoid this potential interaction, use orlistat (Xenical, Alli) and fish oil at least 2 hours apart.
Medicines that slow blood clotting (anticoagulants/antiplatelet agents) interact with fish oil
Fish oil may slow blood clotting. Taking fish oil along with medications that slow blood clotting can increase the likelihood of bruising and bleeding.
